This invention relates to the field of communications. More particularly, methods and apparatus are provided for establishing a communication connection between a device and a communication network.
The 3rd Generation Partnership Project (3GPP™) is a collaboration among several telecommunications standards bodies to provide standards for mobile communications, particularly for GSM (Global System for Mobile communication) networks and devices. Some of the specifications issued by 3GPP include GPRS (General Packet Radio Service), EDGE (Enhanced Data rates for GSM Evolution), W-CDMA (Wideband Code Division Multiple Access) and LTE™ (Long Term Evolution).
LTE is a standard for wireless communication designed to provide high-speed data access for mobile telephones and other devices (e.g., tablet computers). LTE implements a flat IP (Internet Protocol) architecture to provide lower latency compared to earlier (e.g., 2G and 3G) architectures. Therefore, all communication services, including voice and data, are carried by IP, although it provides fall-back capability to circuit-switched technology for voice connections, and is interoperable with previous generations of mobile communication technology.
Among its benefits, LTE supports both frequency-division duplexing (FDD) and time-division duplexing (TDD), allows different quality of service (QoS) characteristics for different communication channels/connections, and supports scalable bandwidth allocations. Although initially implemented only on GSM and UMTS™ (Universal Mobile Telecommunications System) networks, CDMA (Code Division Multiple Access) network operators are also migrating to the LTE architecture. LTE Advanced has been proposed and is in development as an enhancement to the LTE standard, and will provide even higher data rates and support more users per cell.
The LTE specification provides for two states of user equipment relative to the LTE network and the Evolved Packet System (EPS): EMM_DEREGISTERED and EMM_REGISTERED, where EMM stands for EPS Mobility Management. In the EMM_DEREGISTERED state, user equipment has no active signaling connection with the network (e.g., it is camped or turned off), and therefore has no immediate access to packet services through the EPS; in the EMM_REGISTERED state, it does. Transition to the EMM_REGISTERED state, however, may require several messages to be exchanged between the equipment and the network, especially if one or more default access points are unavailable. The more signaling and processing required to enter the EMM_REGISTERED state, the more delay there is in establishing a connection and the user's access to the Internet and/or other data services.
The LTE architecture envisions a radio access network (or RAN), comprising evolved nodeBs that communicate directly with user equipment, and a core network that manages user connections. A user's connection context may be purged from the access network when his or her equipment is in the EMM_DEREGISTERED state, and so the faster the equipment can be returned to the EMM_REGISTERED state, the sooner a communication channel can be established through the access network (i.e., a radio bearer) and the sooner full functionality can be returned to the user.